According to The Guardian, U.K. and U.S. officials worked together to collect images of millions of Yahoo webcam chat users, storing them in a top-secret file code named "Optic Nerve."

Compiled between 2008 and 2010, the agencies did not discriminate, capturing photos "regardless of whether individual users were an intelligence target or not," the paper said.

Unsurprisingly, a vast number of those images include sexually explicit content.

Yahoo did not immediately respond to PCMag's request for comment. But the Web giant "reacted furiously" to The Guardian's inquiry, denying prior knowledge of the program, and accusing the GCHQ and NSA of "a whole new level of violation of our users' privacy."

According to the paper, the "Optic Nerve" system was put to use in automated facial-recognition experiments; GCHQ wanted to monitor existing terrorist targets, and find new ones. But instead of collecting entire webcam conversations, the program saved one image every five minutesthe agency's way of complying with human rights legislation, and avoiding a server overload.

A GCHQ spokesman declined to comment on the situation, telling PCMag that "all of GCHQ's work is carried out in accordance with a strict legal and policy framework which ensures that our activities are authorized, necessary, and proportionate, and that there is rigorous oversight, including from the Secretary of State, the Interception and Intelligence Services Commissioners, and the Parliamentary Intelligence and Security Committee."

All operational processes, the spokesman said, "rigorously support this position."

The American government got involved when GCHQ needed a system into which it could feed Internet cable tapsthe NSA's XKeyscore search tool, The Guardian reported.

"As we've said before, the National Security Agency does not ask its foreign partners to undertake any intelligence activity that the U.S. government would be legally prohibited from undertaking itself," an NSA spokeswoman said in a statement.

"A key part of the protections that apply to both U.S. persons and citizens of other countries is the mandate that information be in support of a valid foreign intelligence requirement, and comply with U.S. Attorney General-approved procedures to protect privacy rights," she said. "Those procedures govern the acquisition, use, and retention of information about U.S. persons."

U.K. laws, however, don't follow the same restrictions. According to The Guardian, GCHQ is under no requirement to prevent Americans' images from being accessed by British analysts without individual consent.

Stephanie began as a PCMag reporter in May 2012. She moved to New York City from Frederick, Md., where she worked for four years as a multimedia reporter at the second-largest daily newspaper in Maryland. She interned at Baltimore magazine and graduated from Indiana University of Pennsylvania (in the town of Indiana, in the state of Pennsylvania) with a degree in journalism and mass communications.
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